JPH077031B2 - Radiation noise measuring device - Google Patents

Description

The present invention relates to an apparatus for measuring electromagnetic noise (hereinafter simply referred to as noise) radiated from electronic equipment.

[Conventional technology]

Due to the rapid development of electronic devices, the noise generated by the electronic devices themselves has become a serious problem today. Many appear as reception obstacles to radio and television. As a phenomenon that cannot be ignored, these radio wave disturbances have been internationally reported to control the intensity of noise generated from electronic devices. In reality, these reports are legalized in each country and regulated under the law.

Noise generated from such electronic devices is measured separately for conduction noise and radiated noise, and a standard value is set for each. On the maker side, we will try to meet the standard values. Conducted noise can be easily measured in a shielded room. On the other hand, radiation noise is difficult to measure, and is generally measured over a long period of time.

Conventionally, in order to measure such radiated noise, an electronic device is mounted on a turntable, which is rotated, and the receiving antenna installed at a certain position searches for the direction in which the maximum intensity in the 360 ° direction can be obtained, and the maximum intensity. Fix the turntable in the obtained position. Then, the receiving antenna is raised in the vertical direction, and the receiving antenna is fixed at the position of the antenna height where the maximum strength is obtained, and the electric field strength thereof is measured. This method is generally internationally standardized.

[Problems to be solved by the invention]

In this measuring method, the electric field strength is measured by rotating the turntable and raising the antenna, which requires a long time for the measurement.

Therefore, the applicants of the present application have already proposed the measuring method described in Japanese Patent Application No. 61-248384. In this measurement method, the turntable is rotated in one direction, the antenna is slowly raised, the receiving antenna is a wideband antenna, and the received signal is measured with a receiver having a frequency sweep function over a wide frequency span. Therefore, the measurement can be completed in a very short time. However, in this case, if the receiver is used in a wide frequency band and at a high speed sweep (for example, several hundred msec or less), the resolution becomes poor. As a result, if a high-speed sweep is performed for the purpose of short-time measurement, an error will occur.

[Means for solving problems]

In order to eliminate this drawback, the present invention uses a plurality of receivers, distributes noise signals to them, and makes each receiver share a different frequency region, thereby achieving high accuracy and high speed. It enables measurement.

That is, according to the present invention, when measuring the noise radiated from an electronic device, the electronic device is installed on a turntable, and a wideband antenna is used as a receiving antenna for receiving the noise. In a radiation noise measuring device for measuring the noise by moving the wideband antenna in a vertical direction while rotating a table, an output signal of the wideband antenna is distributed to a plurality using a distributor, and The input signals are input to a plurality of receivers having sweeping functions of different frequency bands, and each of the receivers receives each of the frequency bands obtained by frequency-dividing a predetermined measurement region. A radiation noise measuring device is obtained.

〔Example〕

 Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 shows the arrangement of a device for measuring noise radiated by an electronic device and the direction of a radio wave to be measured according to an embodiment of the present invention. The electronic device 1 is a turntable 2
Placed on top, the turntable 2 rotates. A receiving antenna 4 is installed at a position away from the electronic device 1 by a distance D, and the antenna 4 is freely movable on an antenna mast 5. In this arrangement, the receiving antenna 4 is slowly raised while rotating the turntable 2. Of the noise radiated by the electronic device 1, the reception antenna 4 receives a composite wave of two waves of the direct wave 6 toward the reception antenna 4 and the floor reflected wave 7. The receiving antenna 4 and the turntable are moved until the phase of the direct wave of the received composite wave and the phase of the floor reflected wave match. Since the phase of this direct wave and the floor reflected wave changes for each frequency, the antenna 4 is moved for each frequency to adjust the phase, and the maximum reception intensity is guided from the antenna 4 to the receiver 9 by the coaxial cable 8. , Receiver 9
Measure the reception strength with. The frequency to be measured is generally 25MH
It is from z to 1 GHz, and a wideband antenna must be used for continuous measurement. Also, the receiver 9
Similarly, for example, a spectrum analyzer can be used to measure the signal strength in a wide band, and the sweep is always performed in the frequency span that can be received by the antenna.

Here, in the present embodiment, a plurality of receivers 9 are used. At this time, as shown in FIG. 1, a coaxial cable 8 and a signal distributor are used to connect the receiving antenna 4 and each of the plurality of receivers 9. 12
And are used to distribute the reception signal of the reception antenna 4 to the plurality of receivers 9. The plurality of receivers 9 have sweeping functions for different frequency bands. Then, each receiver 9 is made to receive each of the above-mentioned frequency bands obtained by frequency-dividing a predetermined measurement region (25 MHz to 1 GHz described above). At this time, the frequency sweep width is selected so that the field capability is sufficiently obtained. By thus determining the frequency sweep width of each receiver 9, high-speed sweep is possible, and high-speed measurement can be realized in a short time.

As described above, in this embodiment, the noise measurement can be completed in an extremely short time. Each receiver 9 always holds the maximum intensity of reception by the maximum hold function of the reception level.

The measurement values obtained by each of the receivers 9 can be easily read by adding a computer as shown in FIG. In FIG. 3, 14 is a control signal line (interface bus, etc.), 15 is a control computer main body (CPU), 16 is a printout device such as a printer or XY plotter, and 17 is a computer display device (CRT display). Etc.). Also,
If a graph function is added to the control computer body 15,
The data of each receiver 9 measured independently can be easily displayed as a continuous figure by the XY plotter printer 16 or the like.

〔The invention's effect〕

As described above, according to the present invention, a noise signal is distributed and given to a plurality of receivers, and each receiver receives each of frequency bands obtained by frequency-dividing a predetermined measurement region, thereby achieving high accuracy. Moreover, it becomes possible to measure the radiation noise of the electronic device at a high speed.

[Brief description of drawings]

FIG. 1 is a block diagram of a main part of a radiation noise measuring device according to an embodiment of the present invention, FIG. 2 is a block diagram schematically showing the whole radiation noise measuring device, and FIG. 3 is a radiation noise measuring device. FIG. 3 is a block diagram of a computer connected to the device. 1 ... Electronic equipment, 2 ... Turntable, 3 ... Ground plane, 4 ... Receiving antenna, 5 ... Antenna mast, 6 ... Direct wave, 7 ...
Reflected wave, 8… Coaxial cable, 9… Receiver, 12… Distributor.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-60-174959 (JP, A) JP-A-59-5974 (JP, A) JP-A-54-151479 (JP, A)

Claims (1)

[Claims] 1. When measuring noise radiated from an electronic device, the electronic device is installed on a turntable, a wideband antenna is used as a receiving antenna for receiving the noise, and the turntable is rotated. In the radiated noise measuring device that moves the wideband antenna in the vertical direction while measuring the noise, the output signal of the wideband antenna is distributed to a plurality of parts using a distributor, and the distributed signal To a plurality of receivers having sweeping functions for different frequency bands, and each of the receivers receives each of the frequency bands obtained by frequency division of the measurement region. .